If a function is linear, what is the shape of its graph?

A linear function is defined by a constant rate of change, which means that as the input (often represented by x) changes, the output (represented by y) changes at a consistent rate. This relationship can be expressed in the form of the equation (y = mx + b), where (m) represents the slope of the line, indicating how steep the line is, and (b) represents the y-intercept, which is the point where the line crosses the y-axis.

When graphed, a linear function produces a straight line because the relationship between the input and output does not curve or bend, remaining proportional throughout. The key characteristic of such a function is that the graph will always maintain a straight trajectory regardless of the range of values taken by x.

Understanding that the other shapes mentioned in the choices—such as a square, a parabola, or a circle—represent different mathematical relationships is essential. A square consists of four straight sides and angles but does not represent a continuous linear function. A parabola indicates a quadratic relationship, characterized by a curved graph. A circle represents a circular relationship, which also implies a change that is not linear. Thus, a linear function distinctly corresponds to the straight line representation in its graph